1. Field of the Invention
The invention relates to a semiconductor device, and more particularly to a metal oxide semiconductor field transistor.
2. Description of Related Art
A high breakdown voltage and a low on-state resistance must be provided to reduce power loss when operating an ultra high voltage device. Currently, array structures are developed to provide higher current while maintaining sufficient breakdown voltage. In layouts of AC-DC products, layout areas may be reduced and the performance of devices may be enhanced through the array structures. As for an ultra high voltage device being developed in present days, a source region and a drain region thereof are formed in a shape of interdigitated fingers. Although a source terminal and a drain terminal having the shape of interdigitated fingers may decrease the layout area, however, a curvature thereof is quite large. A large current is particularly accumulated at the source terminal and/or drain terminal which becomes a breakdown point, thereby decreasing the breakdown voltage of the device.